1. Field of the Invention
The present invention relates to an optical biological information measuring apparatus which measures biological information using light, optical biological information measuring method, biological information decision method, program thereof and recording medium. The invention relates to, for example, an optical fat thickness measuring apparatus which measures a thickness of local panniculus and a tissue oxygen concentration measuring apparatus which measures tissue oxygen concentration of muscle.
2. Related Art of the Invention
As a conventional optical biological information measuring apparatus which measures biological information such as a thickness of local fat, there has been one that has a light-emitting section and a light-receiving section arranged on the surface of a living body and measures the thickness of fat from diffused/reflected light (for example, see Japanese Patent Laid-Open No. 11-239573 (e.g., FIG. 6)).
FIG. 20 is a block diagram of a conventional panniculus thickness measuring apparatus (e.g., see Japanese Patent Laid-Open No. 11-239573 (e.g., FIG. 6)). A light-emitting element 3 is driven by a driving circuit 2 through a command from a CPU 1 to emit near-infrared light. This near-infrared light passes through panniculus 4, is diffused/absorbed, and the reflected light thereof is received by light-receiving elements 5, 6, 7. The CPU 1 decides which output of the light-receiving elements 5, 6, 7 should be applied according to a measuring region selected by a button at a measuring region selection input section 10 and operates an analog switch 8. Then, one light-receiving input is selected by the analog switch 8 and captured by the CPU 1 through an AMP 9. Then, the CPU 1 performs calculations based on the light-receiving input and displays the measuring result on a measured value display section 50.
Furthermore, in another conventional technique, a light-emitting section and a light-receiving section have been arranged so as to obtain a plurality of different optical path lengths and variations have been corrected in skin color, etc., from a plurality of amounts of light received corresponding to the different optical path lengths obtained by the light-receiving elements (e.g., see Japanese Patent Laid-Open No. 2000-155091 (e.g., FIG. 4)).
Furthermore, there has been a further conventional technique that measures a force with which a measuring probe is pushed against a living body, adopts a protruding shape for the measuring probe to thereby correct variations in the fat thickness, stabilize the fat thickness and improve measuring repeatability (e.g., see Japanese Patent Laid-Open No. 2003-310575).
However, because the measuring surface which contacts a living body is flat in the panniculus thickness measuring apparatus having a conventional structure, it is not easy for the user to find out where a measuring region to be measured should be contacted with in the measuring surface. Furthermore, since light emitted from the light-emitting element is infrared which is invisible to human eyes, it has been impossible for the user to know whether the region to be measured has been actually measured or not. Furthermore, since it is difficult to align the measuring region, measuring positions differ from one measurement to another, thus degrading measuring repeatability. Furthermore, since the thickness of panniculus of a living body is not uniform, simple displacement in every measurement would result in a large measuring error. When measuring the effects of exercise or esthetic treatment, a large measuring error caused by displacement would result in a serious problem in checking the effects, and so it has been always necessary to measure the effects at the same position.
Furthermore, when a user of a panniculus thickness measuring apparatus having a conventional structure measures regions such as the upper arm, back of the thigh or back whose panniculus is a matter of concern, measuring regions are not easily visible to the measurer, and for this reason the measuring repeatability deteriorates due to displacement in every measurement, thus making self-measurement impossible. Since the thickness of panniculus of the back of the upper arm is not uniform, if the measuring position changes in every measurement, simple displacement would amount to a large measuring error.
The present invention has been implemented in view of the above described conventional problems and it is an object of the present invention to provide an optical biological information measuring apparatus, optical biological information measuring method, program thereof, recording medium and biological information decision apparatus using them capable of measuring biological information with high alignment accuracy.